Several systems for projecting advertising images onto a display surface, including for outdoor advertising such as billboards, have been previously described. For example, U.S. Pat. No. 5,570,138, describes a projected advertising system having a retractable projection screen which is implemented onto a standard fixed billboard. The fixed billboard image is displayed during the daytime. During the nighttime, the projection screen is automatically unrolled in front of the fixed billboard image and a projector placed in front of the screen is used to project advertising images onto the screen. The system can be controlled by photoelectric light sensors or remotely controlled via radio wave signals. Similar systems utilizing display screens and projectors are described in U.S. Pat. Nos. 3,198,066; 3,020,798; and 2,491,184.
There are many advantages of a projection advertising display over a fixed image advertising display. For one, the image can be more easily changed by simply changing the projected image rather than having to physically replace the conventional static advertisement adhered to the advertising surface (such as a billboard, poster, painting, etc.). In addition, moving video images can be displayed, whereas a fixed image display can at best display one of several images (for example by rotating panels, or reeling a screen).
Video advertising has been implemented on video displays such as LED screens, LCD screens and plasma TV screens, but such screen technology is very expensive and the screen sizes are generally limited to being much smaller than typical outdoor billboards.
A digital projection advertising image has several advantages over the aforementioned systems. The image from a relatively small projector can be made very large with the use of lenses; moreover, a large image can be projected at a fraction of the cost of a comparably-sized LED or LCD display. In addition, it is possible to project the image directly onto the exterior surface of an existing building such that there is very little physical infrastructure cost as with building a billboard or mounting a screen. Thus, the real estate is not physically affected as with other types of video or static billboard advertising.
Indeed, a limited amount of projected video advertising has been previously done by projecting the advertising image onto an exterior surface of a building using a projector placed on or in an adjacent building. The image is projected directly onto the building wall without the use of a screen. However, all such projected video advertising has been done either illegitimately without permission of the property owners or more rarely, as temporary event advertisements. Because such advertisements are being placed illegally, the projector requires local control of their operation with at least one person remaining on-site to monitor and protect the projector. This also requires that the projector be easily moved in the event of detection by unreceptive property owners. Because of the impermanence of such advertisements, the projectors have not been designed to withstand prolonged exposure to outdoor environmental conditions and the projection display cannot be offered to an advertiser on a long-term or even permanent basis.
Accordingly, there is need for a digital projection advertising display system and method which overcomes the shortcomings and disadvantages of previous systems and methods.